OBJECTIVETo compare the impacts of different beverages on plaque pH of caries-sensitive and caries-free children and to evaluate the applicability of in situ pH measurements in human dental plaque using Beetrode microelectrode.

METHODSThe subjective population consisted of 20 children (aged 3-5 years). Ten of them were caries-free(dmft = 0); the other were caries-active (dmft > 4). The dental plaque pH were measured in situ with a pH microelectrode within 1 h after drinking three different beverages respectively. Then the resting pH value (pHrest), minimum pH value (pHmin), the range of the pH (deltapH) was analyzed by ANOVA. Results There was a significant difference in pHrest between caries-free and caries-sensitive children. All the pH responses in the plaque following drinking three different beverages showed a classic Stephan-type response. The differences of the pHmin, deltapH in sound sites were no statistic significance (P > 0.05) after drinking beverages in caries-free children. However the changes in the caries-sensitive group were more pronounced than the non-caries group. There were significant differences on the pHmin, deltapH among different beverages (P < 0.05).

CONCLUSIONThe cariogenicity of plaque in caries-active children was stronger than that of the caries-free group. Different beverages have different potential cariogenicity.